Diving into the Atomic Scale
Delving into what everyday objects are made of lead to observations which are at least as “weird” and whose models are at least as unintuitive.
It was discovered that all material is made up of atoms in various arrangements and that these atoms take up only a miniscule volume of that material. Even the hardest and heaviest of materials is predominantly empty space. Although that is not obvious to the casual observer or directly observable without special equipment, there is little yet which would be considered “weird” or which would feel alien to what we see in the world around us.
In the 19th century, atoms were thought of as having a central positively charged nucleus surrounded by orbiting negative electrons analogous to planets orbiting the sun in the solar system but with the electrostatic force replacing gravity [Larmour 1897]. This was a picture which was familiar to many people and so an attractive path to explore but it soon became clear that this was not a correct one. The theory which worked was much “weirder”.
Moving into the sub-atomic scale
We can investigate what atoms are made of but, just as when we look at the cosmic scale, we move further away from the familiar and from what is intuitive to us.
Sub-atomic particles do not behave like planets or like tiny billiard balls with definite properties. Instead, physics describes an unfamiliar world governed by probabilities, uncertainty, and phenomena so strange that even Einstein resisted accepting them.
For example:
- We cannot know for sure the location of an object, only the probability of finding it at a specific location if we look.
- A particle, such as an electron. can travel through two slits at once and then recombine in a way which would be expected for a wave.
- Two or more particles can become entangled such that, even if they are a huge distance apart, a measurement of one will instantaneously cause a change in the other..
Again, as we start to look at phenomena which are at scales which our brains were not designed to directly understand, we come up against models which work to make predictions but which are not clearly understood. In fact, Richard Feynman famously stated in his book The Character of Physical Law (1995), “I think I can safely say that nobody understands quantum mechanics.” In 1952, Niels Bohr said: “Those who are not shocked when they first come across quantum theory cannot possibly have understood it.”.